For me it would be a dollars and cents issue. Building up to an Adventure package is about $1700 for the transfer case and $750 for the rear locker. Addiing a front locker is significantly more as you need a whole new carrier. So, to move to an "equivalent" 07 should be $2500 or less. Equivalent assumes equal miles, equal trim, etc.
A big benefit of 07 and newer is the 100K powertrain warranty. I would put that value around $1500, near the price of a GMPP though of course it doesn't cover as much. But I've definitely seen more than $1500 (heck, more than $3000) in value from that powertrain warranty. Mind that you need to keep an eye on the years too as it is five years so I'm going to hit 100K just a few months before I hit five years.
07s and newer have a bit more power. That never sucks.
07 and newer may have less miles. That is worth something.
For me, if I could get an 07 or newer Adventure, with less miles for maybe $6000 or less difference after the value of your 06 I might do it. Anything more than that must have great value - never, ever offroad; low miles, V8, front/rear lockers, etc.